KSO - for Keep Stuff Out! New from Vibram, these Five Fingers are re-designed off of the Vibram Five Finger Classics, but with higher coverage on your feet to keep stuff out! KSO"s are made with a thin, abrasion-resistant stretch polyamide mesh fabric fits up over your arch on the foot - for comfort and quick drying. A flexible, non-marking TC1 performance rubber sole is razor-siped to enhance grip over a variety of terrain.